Snow cutters

ABSTRACT

The invention concerns snow cutters having a rotatable drum cutter and a rotatable drum ejector, the cutter and ejector being disposed coaxially and horizontally, and transversely with respect to the direction of travel of the snow cutter. Means are provided adapted to rotate the ejector at a higher rotational velocity than the cutter. Such snow cutters have the advantage of good manoeuvrability and large snow throwing distances.

States Patent 1 [111 3,755,931

Gisler Sept. 4, 1973 [54] SNOW CUTTERS 2,198,237 4/1940 Voorden'nari 37/43 E I 2 93 B l. [75] Inventor: Hans Gisler, Cantor of Bern, 5 4/1 9 ehrens et a] 37/43 D Switzerland FOREIGN PATENTS OR APPLICATIONS 627,518 9/l96l Canada 37/43 E [73] Assignee: Firma Marcel Boschung, Schmitten (Canton of Fribourg), Switzerland [22] Filed: Aug. 4, 1971 Primary ExaminerRobert E. Pullirey Assistant Examiner-Eugene H. Eickholt [21] Appl' 168307 AttorneyBeveridge & De Grandi 823,673 1/1938 France 37/43 [52] US. Cl. 37/43 E, 198/217 [57] ABSTRACT 51 11m. Cl Etllh 5/00 5s 1 Field of Search 37/43, 20, 24; The mvemm" cmcems a rotatable 198/217 drum cutter and a rotatable drum ejector, the cutter and ejector being disposed coaxially and horizontally,

[ 56] References Cited and transversely with respect to the direction of travel of the snow cutter. Means are provided adapted to ro- UNITED STATES PATENTS tate the ejector at a higher rotational velocity than the Latta E cutten such now cutters have the advantage of good 3,398,470 8/1968 9 et 37/43 E manoeuvrability and large snow throwing distances. 2,353,928 7/1944 Plltz 37/43 D 3,043,028 7/1962 Merry et al. 37/43 E 7 Claims, 4 Drawing Figures PATENTEDSEP 4m 3.755 ;931

sum 1 or 2 mvennl IANS GISLEL 8! mm 4 m SHEEN 2 0f 2 HHENYO MB 645 LEE E si- A TTOLNEYS SNOW currsns BACKGROUND OF THE INVENTION 1. Field of Invention The present invention relates to snow clearing machines and more specifically to the class of snow clearing machines known as snow cutters.

2. Description of the Prior Art Snow clearing machines hitherto known many be divided into three main classes viz snow cutters, rotary snow ploughs and rotary cutter snow ploughs.

The class of snow clearing machines known as snow cutters comprise a unitary drum disposed transversely with respect to the direction of travel of the snow clearing machine about a horizontal axis. Upon one cylindrical zone of the drum is mounted snow cutting means and upon another snow ejector means. The cutting means is generally adapted to cause cut snow to traverse the drum to be presented to the ejector means whereupon it is ejected through a discharge duct.

The class of snow clearing machines known as rotary snow ploughs are provided solely with snow ejectors which consist of a rotor rotatable about an axis parallel to the direction of travel of the snow clearing machine. The snow to be cleared is driven by the rotor of the ejector through a discharge duct.

The class of snow clearing machines known as rotary cutter snow ploughs are similar in some respects to snow cutters hereinbefore described. They differ inasmuch as the drum carries only snow cutting means. Instead of ejector means mounted on the same drum as the cutting means, a separate rotary ejector is provided having a rotor disposed rearwardly of the cutter drum with the axis thereof extending parallel to the direction of travel of the snow clearing machine. Conveying means is also provided to convey the snow to the rotor of the ejector whereupon it is ejected through a discharge duct.

Thus, snow cutters are of compact construction in the direction of travel thereof allowing good manoeuvrability. They are subject to the disadvantage that in order to achieve satisfactory performance from the cutting means relatively slow rotational cutting velocities are required This limits the rotational velocity of the ejector means and so the snow throwing distances of snow cutters is generally low.

Rotary snow ploughs have large snow throwing distances but are of limited application since the snow clearing capacity per sweep thereof is low and relatively large areas of snow remain uncleared They are only usefully employed in clearing new or soft snow.

Some rotary cutter snow ploughs have relatively high performance cutting means i.e., a relatively high tuming moment, and in addition relatively large snow throwing distances. However, in view of the onebehind-the-other arrangement of the cutting drum, the snow conveying means and the rotary ejector the machine is relatively long in the direction of travel thereof and manoeuvrability thereof is consequently poor.

SUMMARY OF THE INVENTION The snow cutter of the present invention has a compact construction in the direction of travel therof allowing good manoeuvrability. In addition it has a high performance cutting means i.e., a high turning moment at the cutter drum and also ejector means having a relatively large throwing distance. The snow cutter of the present invention comprises at least one rotatable cutter drum, cutting means mounted on the cutter drum, at least one rotatable ejector drum, ejector means mounted on the ejector drum, the cutter drum and ejector drum being substantially coaxial and being disposed horizontally and transversely with respect to the direction of the travel of the snow cutter, and means adapted to rotate the ejector drum at a higher rotational velocity than that of the cutter drum.

Objects and advantages will appear from the following description of embodiments of the invention, when considered in connection with the accompanying drawings, and the novel features will be particularly pointed out in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a section along the line H l of FIG. 2,

FIG. 2 is a side view of a snow cutter of a first embodiment,

FIG. 3 is a schematic front view of the cutter and ejector drum of a snow cutter of a second embodiment and FIG. 4 is a section though a cutter cowling of a snow cutter of a third embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In a first embodiment shown in FIGS. 1 and 2 a snow cutter comprises an ejector drum 3% disposed intermediate two laterally arranged cutter drums, all three drums 1, 2 and 3 being mounted about a common drive shaft. The drums l, 2 and 3 are horizontally disposed within a housing, the drive shaft 4 extending transversely with respect to the direction of travel of the snow cutter and being located adjacent to the ends thereof in ball races rigidly fixed to the walls of the housing. The ends of the drive shaft 4 project from the walls of the housing.

The cutter drums 1 an 2 are, by means of ball races, mounted on the drive shaft d and are thus able to rotate relatively with respect to the drive shaft 4. The ejector drum 3 is lteyed to the drive shaft 4.

The ejector drum 3 is provided with ejector means in the form of a series of radially extending paddle-like ejector buckets 7;

The cutter drums l and 2 are each provided with cutting means in the form of three continuous helical cutter blades 5 and 6, the helical turns of the blades on one cutter drum extending in an opposed sense with respect to those on the other cutter drum.

One free end of the drive shaft 4 disposed externally of the housing carries a chain sprocket. A cooperating chain sprocket is mounted on the end of a parallel shaft 9, a chain a passing around the two sprockets to drivably connect the drive shaft 4 and shaft 9. The end of the shaft 9 remote from the chain sprocket is connected through a coupling 10 and a n'ghtangle gear II to a power input shaft 12 which delivers dive to the snow cutter.

Internally of the housing and internally of each cutter drum l and 2 adjacent each end of the drive shaft 4 is mounted a pair of chain sprockets. One of said chain sprockets of each pair is keyed to the drive shaft 4, the other being rotatable about the drive shaft 4 by means of a ball race but being rigidly connected to a mounting flange of the respective cutting drum. An idler gear comprising two chain sprockets is mounted on the housing adjacent each pair of chain sprockets mounted on the drive shaft 4 and is drivably connected to the pair of chain sprockets by means of two chains (not shown). Each idler gear 13 together with each pair of chain sprockets and connecting chains constitute a reduction gear system 14 from the drive shaft 4 to the cutter drums l and 2.

In operations, drive is transmitted from the power input shaft 12 through the coupling 10, shaft 9 and chain 8 to the drive shaft 4. As the ejector drum 3 is keyed to the drive shaft 4, the ejector drum rotates at the same rotational velocity as the drive shaft 4. Drive to the cutter drums l and 2 is transmitted from the drive shaft through each reduction gear system 14. Hence the cutter drum rotates at a lower rotational velocity than that of the drive shaft i.e., the ejector drum 3 rotates at a higher rotational velocity than that of the cutter drums l and 2. The difference in rotational velocity of the ejector and cutter drums will naturally depend on the transmission ratio of the reduction gear system 14.

In use, when the snow cutter advances through a bed of snow, the cutter blades 5 and 6 on each of the relatively slowly rotating cutter drums l and 2 slice through the snow. In addition, by virtue of the opposed helical formation of the cutter blades 5, the cut or loose snow is caused to traverse the cutter drums towards the relatively quickly rotating ejector drum 3 to be presented to the ejector buckets 7 and ejected.

It will be appreciated that the snow throwing distance of the snow cutter of the embodiment together with the performance of the cutter to cut and convey the snow is far superior to the prior art snow cutters of unitary drum construction.

In addition, by virtue of the coaxial disposition of the cutter and ejector drums a compact construction in the direction of travel of the snow cutter is achieved allowing good manoeuvrability.

In a second embodiment, the cutter and ejector drums l, 2 and 3 of the snow cutter of the first embodiment shown in FIGS. 1 and 2 are replaced by the cutter and ejector drums, again designated 1, 2 and 3, shown in FIG. 3. As in the cutter drums of the first embodiment, the cutter drums l and 2 of the second embodiment are provided with three helical cutter blades 5 and 6 respectively. However each cutter blade of the second embodiment is provided with a guide plate in the form of a circumferentially projecting extension 15 of the end thereof adjacent the ejector drum 3. As is shown in FIG. 3, each guide plate 15 extends circumferentially in an oposed sense to the direction of rotation of the ejector drum 3. The length of each extension or guide plate 15 is less than the circumferential distance between adjacent cutter blades so to allow a gap 16 between the free end of the guide plate and an adjacent cutter blade. A circumferential length of the guide plate 15 of between one-half and two-thirds of the circumferential distance between the cutter blades is found in practice to give the best results.

In operation of the snow cutter of the second embodiment cut snow traverses the cutter drums l and 2 between adjacent cutter blades through the gaps B6 and into the ejector buckets 7. Since the ejector drum 3 rotates more quickly than the cutter drums I and 2, snow having passed into the ejector buckets is unable to pass back due to the blocking effect of the guide plates 15. Thus, the distance between an ejector bucket being filled with snow and the end of an adjacent guide plate 15 quickly decreases so that the guide plate 15 abbuts the sides of the ejector bucket to prevent loss of snow. In this manner, the ejector capacity of the ejector buckets is greatly increased and up to 30 percent increase in ejector capacity is possible over the snow cutter described in he first embodiment.

To achieve an increase in ejector capacity by increasing the circumferential length of the side walls of each ejector bucket and thus the volumetric capacity thereof is not feasible as it is accompanied by disadvantages. Thus, the snow passing between the cutter blades towards the ejector drum would be urged against the extended side walls of the more quickly rotating ejector buckets which would act as a barrier to its entry into the ejector buckets and cause frictional drag between the two drums. By a construction in accordance with the second embodiment, this disadvantage is effectively overcome.

In a third embodiment of the invention shown in FIG. 4, the guide plates 15 of the second embodiment which are integral with the cutter blades 5 and 6 are replaced by two guide plates 18 (only one of which is shown) mounted on the cowling 17 of the cutter and ejector drums, one on each side of the ejector buckets 7 independently thereof. In this manner, the advantages achieved by the construction according to the second embodiment are likewise achieved.

MODIFICATIONS In FIGS. 1 and 2 a preferred embodiment of the invention is shown having a power input shaft 12 delivering drive to the ejector drum directly and drive to the cutter drums being transmitted through a reduction gear. Alternatively however, it is possible to deliver drive directly to the cutter drum and to deliver drive to the ejector drum through a step'up gear system. It would also be conceivable to dispense with the drive interconnection between the cutter drums and the ejector drum, and to have independent driving means for each type of drum arranged to drive the ejector drum at a higher rotational velocity than the ejector drum. Thus, hydraulic or electric motors could be housed within each cutter drum and ejector drum, the latter choice allowing continuous regulation of rotational speed differences between the drums. Another possibility is to replace the sprockets and chains of the reduction gear system exemplified by a gear train of meshing spur gears or a sun and planet gear system. Such gear train or system could be in the form of a gear box allowing different transmission ratios to be selected.

Although two cutter drums and one ejector drum have been described, the number of each type of drum may naturally be varied depending on the size of the snow cutter and the required snow clearing capacity. Thus, two groups of the drum systems described may be employed in large cutters, or alternatively, one cutter and one ejector drum may be employed in smaller snow cutters.

While I have shown and described the preferred form of the present invention and have suggested modifications therein, other changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of the invention.

What is claimed is:

1. A snow cutter including a frame; a pair of spaced apart cutter drums, each said cutter drum being rotatably mounted on said frame; means mounted on said frame and operably associated with the cutter drums for rotating the cutter drums at the same speed of rotation and in the same direction of rotation; an ejector drum, said ejector drum being rotatably mounted on said frame intermediate the cutter drums; means mounted on said frame and operably associated with the ejector drum for rotating the ejector drum independently of the cutter drums, in the same direction as the cutter drums and at a greater speed than the cutter drums; said cutter drums each including helical cutting means for cutting snow and feeding the cut snow to the ejector drum, the spiral of the helical cutting means of one cutter drum being oppositely directed to the spiral of the helical cutting means of the other cutter drum, each spiral being directed to feed cut snow toward the ejector drum, said ejector drum including a plurality of radially extending ejector blades disposed at the discharge juncture of the oppositely directed helical cutting means of the cutter drums.

2. A snow cutter as specified in claim 1 including a cowling mounted on said frame and extending circumferentially in a spaced apart relation about at least a segment of the cutter drums and ejector drum, a plurality of arcuately shaped guide plates disposed in spacedapart positions to each side of the ejector drum to form a plurality of passageways through which the blades of the ejector drum move, each guide plate being shaped to generally conform to the height of the ejector blades and being disposed generally curvilinearly normal to the ejector drum an extending circumferentially and independently thereof, the helical cutting means of each cutter drum comprising at least two helically disposed cutting blades, the circumferential length of the guide plates being substantially less than the circumferential distance between adjacent cutting blades.

3. The snow cutter of claim 2, wherein the circumferential length of the guide plates is between one-half and two-thirds of the circumferential distance between adjacent cutting blades.

4. The snow cutter of claim 2, wherein the said guide plates are circumferentially disposed extensions of the ends of the cutter blades adjacent the ejector drum.

5. The snow cutter of claim 2, including a cowling for the cutter and ejector drums, the guide plates being mounted on the cowling.

6. A snow cutter including at least one rotatable cutter drum, cutting means mounted on the cutter drum, the cutting means on the cutter drum comprising at least two spaced apart helical cutting blades, at least one rotatable ejector drum, ejector means mounted on the ejector drum, the cutter and ejector drums being substantially coaxial and disposed horizontally and transversely with respect to the direction of travel of the snow cutter, means operatively associated with the ejector drum and adapted to rotate the ejector drum at a higher rotational velocity than that of the cutter drum, and a plurality of arcuately shaped elongated guide plates disposed generally curvilinearly normal to the ejector drum and extending circumferentially and independently thereof, the circumferential length of the guide plates being less than the circumferential distance between adjacent cutting blades.

7. A snow cutter including at least one rotatable cutter drum, cutting means mounted on the cutter drum, at least one rotatable ejector drum, ejector means mounted on the ejector drum, the cutter and ejector drums being substantially co-axial and disposed horizontally and transversely with respect to the direction of travel of the snow cutter, drive means interconnected to the ejector drum for rotation thereof, and a reduction gear system for rotation of the cutter drum at a lower rotational velocity than the ejector drum, the reduction gearing system being driveably interposed between the ejector drum and cutting drum and disposed internally of the cutter drum. 

1. A snow cutter including a frame; a pair of spaced apart cutter drums, each said cutter drum being rotatably mounted on said frame; means mounted on said frame and operably associated with the cutter drums for rotating the cutter drums at the same speed of rotation and in the same direction of rotation; an ejector drum, said ejector drum being rotatably mounted on said frame intermediate the cutter drums; means mounted on said frame and operably associated with the ejector drum for rotating the ejector drum independently of the cutter drums, in the same direction as the cutter drums and at a greater speed than the cutter drums; said cutter drums each including helical cutting means for cutting snow and feeding the cut snow to the ejector drum, the spiral of the helical cutting means of one cutter drum being oppositely directed to the spiral of the helical cutting means of the other cutter drum, each spiral being directed to feed cut snow toward the ejector drum, said ejector drum including a plurality of radially extending ejector blades disposed at the discharge juncture of the oppositely directed helical cutting means of the cutter drums.
 2. A snow cutter as specified in claim 1 including a cowling mounted on said frame and extending circumferentially in a spaced apart relation about at least a segment of the cutter drums and ejector drum, a plurality of arcuately shaped guide plates disposed in spaced-apart positions to each side of the ejector drum to form a plurAlity of passageways through which the blades of the ejector drum move, each guide plate being shaped to generally conform to the height of the ejector blades and being disposed generally curvilinearly normal to the ejector drum an extending circumferentially and independently thereof, the helical cutting means of each cutter drum comprising at least two helically disposed cutting blades, the circumferential length of the guide plates being substantially less than the circumferential distance between adjacent cutting blades.
 3. The snow cutter of claim 2, wherein the circumferential length of the guide plates is between one-half and two-thirds of the circumferential distance between adjacent cutting blades.
 4. The snow cutter of claim 2, wherein the said guide plates are circumferentially disposed extensions of the ends of the cutter blades adjacent the ejector drum.
 5. The snow cutter of claim 2, including a cowling for the cutter and ejector drums, the guide plates being mounted on the cowling.
 6. A snow cutter including at least one rotatable cutter drum, cutting means mounted on the cutter drum, the cutting means on the cutter drum comprising at least two spaced apart helical cutting blades, at least one rotatable ejector drum, ejector means mounted on the ejector drum, the cutter and ejector drums being substantially coaxial and disposed horizontally and transversely with respect to the direction of travel of the snow cutter, means operatively associated with the ejector drum and adapted to rotate the ejector drum at a higher rotational velocity than that of the cutter drum, and a plurality of arcuately shaped elongated guide plates disposed generally curvilinearly normal to the ejector drum and extending circumferentially and independently thereof, the circumferential length of the guide plates being less than the circumferential distance between adjacent cutting blades.
 7. A snow cutter including at least one rotatable cutter drum, cutting means mounted on the cutter drum, at least one rotatable ejector drum, ejector means mounted on the ejector drum, the cutter and ejector drums being substantially co-axial and disposed horizontally and transversely with respect to the direction of travel of the snow cutter, drive means interconnected to the ejector drum for rotation thereof, and a reduction gear system for rotation of the cutter drum at a lower rotational velocity than the ejector drum, the reduction gearing system being driveably interposed between the ejector drum and cutting drum and disposed internally of the cutter drum. 